Author: Uri Blass
Date: 15:29:16 05/02/05
Go up one level in this thread
On May 02, 2005 at 18:21:03, John Merlino wrote: >On May 02, 2005 at 15:44:39, Dann Corbit wrote: > >>On May 01, 2005 at 15:18:05, John Merlino wrote: >> >>>On May 01, 2005 at 12:35:59, chandler yergin wrote: >>> >>>>I think someone posted this position as 'the grind'? >>>> >>>>Shredder finds the Mate. >>>> >>>>[D]1rb3kr/p2q1ppp/1p1N4/3QPP2/8/8/P1P3PP/1R3R1K w >>>> >>>>.e6 Qc7 2.exf7+ Kf8 3.Rbe1 g6 4.fxg6 Be6 >>>> +- (5.66) Depth: 7/21 00:00:45 54kN >>>>1.e6 Qc7 2.exf7+ Kf8 3.Rbe1 Bb7 4.Re8+ Rxe8 5.fxe8Q# >>>> +- (6.16) Depth: 7/21 00:00:47 62kN >>>>1.e6 Qc7 2.exf7+ Kf8 3.Rbe1 Bd7 4.Qe5 Qd8 5.f6 g6 >>>> +- (6.44) Depth: 7/29 00:00:49 77kN >>>>1.e6 Qc7 2.exf7+ Kf8 3.Rbe1 Bd7 4.Qe5 Qd8 5.f6 Qe7 6.Qxe7# >>>> +- (6.69) Depth: 8/22 00:00:55 100kN >>> >>>See this thread: >>> >>>http://www.talkchess.com/forums/1/message.html?423252 >>> >>>As you can see, it is a mate in approximately 15 moves, and you are yet another >>>victim of Shredder's deceptive (or, as I like to put it, "totally wrong") PVs >>>and/or evals. >> >>Many programs will cough up a pound sign in the principal variation and yet >not show a mate score. >> >>The depth of search above is 8 plies, and so these moves: >>... 5.f6 Qe7 6.Qxe7# >>are obviously speculative. > >Ok, I'll believe you, but I still don't get WHY. A program should not show a >mating line in a PV if the mate is not forced, IMHO. I guess that the reason is that Shredder's evaluation does not see the mate. My guess is that Shredder's engine does not know that the pv ends in mate and the interface calculates and find that the pv end with mate score. Note that I think that engines should see mate by evaluation function and Movei does it but there are a lot of engines that do not do it. Uri
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